
var charPool   = "abcdefghigklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890",
    len        = charPool.length;

exports.generateUUID = function(num){


    var code = [];
    for(var i=0; i<num; i++){
        code.push(random());
    }
    return code.join("");

    function random(){
        var index = Math.floor(len*Math.random(len));
        return charPool[index];
    }
}